This section provides background information related to the present disclosure which is not necessarily prior art.
Magnesium and magnesium alloys have the low density, high strength-to-weight ratio, and high stiffness that make them increasingly useful in various applications such as those for automotive and electronic industries. However, the implementation of magnesium and magnesium alloys into various industries is limited because the materials are highly susceptible to corrosion.
Protective coatings have been used to prevent corrosion, but options for applying protective coatings have shortcomings that deter using magnesium and magnesium alloys. For example, various coating techniques have been asserted such as cold spraying and hot diffusion. Cold spraying includes spraying particles on a substrate at a temperature below the melting temperature of the particles. The kinetic energy of the cold sprayed particles causes the particles to plastically deform on the substrate. Cold spraying techniques have limited success on magnesium alloys. Further, cold spraying techniques have the limitation of unwanted porosity of the sprayed layer because the layer is formed by an agglomeration of particles against the substrate.
Another coating technique, hot diffusion has also been used in which the substrate is submerged in a heated powder of the material to be coated onto the substrate. Hot diffusion provides good adhesion of the coating, but the microstructure of the applied protective coating is inconsistent leading to inconsistent coating and performance. Further, hot diffusion techniques require a processing temperature that is close to the melting point of the substrate to be coated. Should the heat from the hot diffusion be sufficient to warp or melt the substrate, the desired properties of the substrate may be undesirably modified or lost.